[PATCH AUTOSEL 6.11 231/244] ksmbd: add refcnt to ksmbd_conn struct

Sasha Levin
2024-09-25T11:53:12Z

From: Namjae Jeon <linkinjeon@kernel.org>

[ Upstream commit ee426bfb9d09b29987369b897fe9b6485ac2be27 ]

When sending an oplock break request, opinfo->conn is used,
But freed ->conn can be used on multichannel.
This patch add a reference count to the ksmbd_conn struct
so that it can be freed when it is no longer used.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/smb/server/connection.c | 4 ++-
fs/smb/server/connection.h | 1 +
fs/smb/server/oplock.c | 55 +++++++++++---------------------------
fs/smb/server/vfs_cache.c | 3 +++
4 files changed, 23 insertions(+), 40 deletions(-)

diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c
index 7889df8112b4e..cac80e7bfefc7 100644
--- a/fs/smb/server/connection.c
+++ b/fs/smb/server/connection.c
@@ -39,7 +39,8 @@ void ksmbd_conn_free(struct ksmbd_conn *conn)
xa_destroy(&conn->sessions);
kvfree(conn->request_buf);
kfree(conn->preauth_info);
- kfree(conn);
+ if (atomic_dec_and_test(&conn->refcnt))
+ kfree(conn);
}

/**
@@ -68,6 +69,7 @@ struct ksmbd_conn *ksmbd_conn_alloc(void)
conn->um = NULL;
atomic_set(&conn->req_running, 0);
atomic_set(&conn->r_count, 0);
+ atomic_set(&conn->refcnt, 1);
conn->total_credits = 1;
conn->outstanding_credits = 0;

diff --git a/fs/smb/server/connection.h b/fs/smb/server/connection.h
index 5b947175c048e..b379ae4fdcdff 100644
--- a/fs/smb/server/connection.h
+++ b/fs/smb/server/connection.h
@@ -106,6 +106,7 @@ struct ksmbd_conn {
bool signing_negotiated;
__le16 signing_algorithm;
bool binding;
+ atomic_t refcnt;
};

struct ksmbd_conn_ops {
diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c
index e546ffa57b55a..8ee86478287f9 100644
--- a/fs/smb/server/oplock.c
+++ b/fs/smb/server/oplock.c
@@ -51,6 +51,7 @@ static struct oplock_info *alloc_opinfo(struct ksmbd_work *work,
init_waitqueue_head(&opinfo->oplock_brk);
atomic_set(&opinfo->refcount, 1);
atomic_set(&opinfo->breaking_cnt, 0);
+ atomic_inc(&opinfo->conn->refcnt);

return opinfo;
}
@@ -124,6 +125,8 @@ static void free_opinfo(struct oplock_info *opinfo)
{
if (opinfo->is_lease)
free_lease(opinfo);
+ if (opinfo->conn && atomic_dec_and_test(&opinfo->conn->refcnt))
+ kfree(opinfo->conn);
kfree(opinfo);
}

@@ -163,9 +166,7 @@ static struct oplock_info *opinfo_get_list(struct ksmbd_inode *ci)
!atomic_inc_not_zero(&opinfo->refcount))
opinfo = NULL;
else {
- atomic_inc(&opinfo->conn->r_count);
if (ksmbd_conn_releasing(opinfo->conn)) {
- atomic_dec(&opinfo->conn->r_count);
atomic_dec(&opinfo->refcount);
opinfo = NULL;
}
@@ -177,26 +178,11 @@ static struct oplock_info *opinfo_get_list(struct ksmbd_inode *ci)
return opinfo;
}

-static void opinfo_conn_put(struct oplock_info *opinfo)
+void opinfo_put(struct oplock_info *opinfo)
{
- struct ksmbd_conn *conn;
-
if (!opinfo)
return;

- conn = opinfo->conn;
- /*
- * Checking waitqueue to dropping pending requests on
- * disconnection. waitqueue_active is safe because it
- * uses atomic operation for condition.
- */
- if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
- wake_up(&conn->r_count_q);
- opinfo_put(opinfo);
-}
-
-void opinfo_put(struct oplock_info *opinfo)
-{
if (!atomic_dec_and_test(&opinfo->refcount))
return;

@@ -1127,14 +1113,11 @@ void smb_send_parent_lease_break_noti(struct ksmbd_file *fp,
if (!atomic_inc_not_zero(&opinfo->refcount))
continue;

- atomic_inc(&opinfo->conn->r_count);
- if (ksmbd_conn_releasing(opinfo->conn)) {
- atomic_dec(&opinfo->conn->r_count);
+ if (ksmbd_conn_releasing(opinfo->conn))
continue;
- }

oplock_break(opinfo, SMB2_OPLOCK_LEVEL_NONE);
- opinfo_conn_put(opinfo);
+ opinfo_put(opinfo);
}
}
up_read(&p_ci->m_lock);
@@ -1167,13 +1150,10 @@ void smb_lazy_parent_lease_break_close(struct ksmbd_file *fp)
if (!atomic_inc_not_zero(&opinfo->refcount))
continue;

- atomic_inc(&opinfo->conn->r_count);
- if (ksmbd_conn_releasing(opinfo->conn)) {
- atomic_dec(&opinfo->conn->r_count);
+ if (ksmbd_conn_releasing(opinfo->conn))
continue;
- }
oplock_break(opinfo, SMB2_OPLOCK_LEVEL_NONE);
- opinfo_conn_put(opinfo);
+ opinfo_put(opinfo);
}
}
up_read(&p_ci->m_lock);
@@ -1252,7 +1232,7 @@ int smb_grant_oplock(struct ksmbd_work *work, int req_op_level, u64 pid,
prev_opinfo = opinfo_get_list(ci);
if (!prev_opinfo ||
(prev_opinfo->level == SMB2_OPLOCK_LEVEL_NONE && lctx)) {
- opinfo_conn_put(prev_opinfo);
+ opinfo_put(prev_opinfo);
goto set_lev;
}
prev_op_has_lease = prev_opinfo->is_lease;
@@ -1262,19 +1242,19 @@ int smb_grant_oplock(struct ksmbd_work *work, int req_op_level, u64 pid,
if (share_ret < 0 &&
prev_opinfo->level == SMB2_OPLOCK_LEVEL_EXCLUSIVE) {
err = share_ret;
- opinfo_conn_put(prev_opinfo);
+ opinfo_put(prev_opinfo);
goto err_out;
}

if (prev_opinfo->level != SMB2_OPLOCK_LEVEL_BATCH &&
prev_opinfo->level != SMB2_OPLOCK_LEVEL_EXCLUSIVE) {
- opinfo_conn_put(prev_opinfo);
+ opinfo_put(prev_opinfo);
goto op_break_not_needed;
}

list_add(&work->interim_entry, &prev_opinfo->interim_list);
err = oplock_break(prev_opinfo, SMB2_OPLOCK_LEVEL_II);
- opinfo_conn_put(prev_opinfo);
+ opinfo_put(prev_opinfo);
if (err == -ENOENT)
goto set_lev;
/* Check all oplock was freed by close */
@@ -1337,14 +1317,14 @@ static void smb_break_all_write_oplock(struct ksmbd_work *work,
return;
if (brk_opinfo->level != SMB2_OPLOCK_LEVEL_BATCH &&
brk_opinfo->level != SMB2_OPLOCK_LEVEL_EXCLUSIVE) {
- opinfo_conn_put(brk_opinfo);
+ opinfo_put(brk_opinfo);
return;
}

brk_opinfo->open_trunc = is_trunc;
list_add(&work->interim_entry, &brk_opinfo->interim_list);
oplock_break(brk_opinfo, SMB2_OPLOCK_LEVEL_II);
- opinfo_conn_put(brk_opinfo);
+ opinfo_put(brk_opinfo);
}

/**
@@ -1376,11 +1356,8 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp,
if (!atomic_inc_not_zero(&brk_op->refcount))
continue;

- atomic_inc(&brk_op->conn->r_count);
- if (ksmbd_conn_releasing(brk_op->conn)) {
- atomic_dec(&brk_op->conn->r_count);
+ if (ksmbd_conn_releasing(brk_op->conn))
continue;
- }

rcu_read_unlock();
if (brk_op->is_lease && (brk_op->o_lease->state &
@@ -1411,7 +1388,7 @@ void smb_break_all_levII_oplock(struct ksmbd_work *work, struct ksmbd_file *fp,
brk_op->open_trunc = is_trunc;
oplock_break(brk_op, SMB2_OPLOCK_LEVEL_NONE);
next:
- opinfo_conn_put(brk_op);
+ opinfo_put(brk_op);
rcu_read_lock();
}
rcu_read_unlock();
diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c
index 4d4ee696e37cd..a19f4e563c7e5 100644
--- a/fs/smb/server/vfs_cache.c
+++ b/fs/smb/server/vfs_cache.c
@@ -863,6 +863,8 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
list_for_each_entry_rcu(op, &ci->m_op_list, op_entry) {
if (op->conn != conn)
continue;
+ if (op->conn && atomic_dec_and_test(&op->conn->refcnt))
+ kfree(op->conn);
op->conn = NULL;
}
up_write(&ci->m_lock);
@@ -965,6 +967,7 @@ int ksmbd_reopen_durable_fd(struct ksmbd_work *work, struct ksmbd_file *fp)
if (op->conn)
continue;
op->conn = fp->conn;
+ atomic_inc(&op->conn->refcnt);
}
up_write(&ci->m_lock);

--
2.43.0